Repeating theodolite



Oct. 7, 1930. J. MAHLER REPEATING THEODOLITE Filed June 18. 1929 www f f f f a 1 1 y 1 u l u n l lll Jn venfor:

Patented Oc't. 7, 1930 UNITED STATES PATENT OFFICE .FIRM or CARL zErss, or

BEPEATING THEGDOLITE Application led Junc 18, 1929. Serial No. 871,928, and in Germany June 20, 1928.

The invention relates toa repeating theodl lite which, as necessary, is provided with-two lclam in devices.A According to the invention ot clamping devices are fixed to the 6 alidade and one of the said clamping devices serves or clamping the alidade'to the horizontal circle'while the other serves for clamping the alidade to the base; further only one adjusting device is provided, -which 1s se- 10 cured to the alidade and serves for adjusting the alidade relatively to the base.

A Compared with the constructions known hitherto, the one concerned in this invention has several advantages. Above all a microm# eter mechanism can be dispensed with'. By arranging on the alidade the .two clamping devices and the only adjusting device required, it is attained that all adjusting knobs always have'the same position relatively to each other as well as tothe surveyor who no longer needs to grope for the different knobs.

' At the same time a simplification of the construction of theaxial system is involved and the attendance. of the apparatus made an easier one, thus allowing the surveyorto work quicker.

A suitable execution of the invention is attained by fitting on the horizontal circle a.V

thin and 'easily' flexible disc or the like, e. g.

' 30 a ring, in such a way that the said disc can lower part of ayrlepeating theodolite corresponding to the invention in .a section containing the vertical nris'fof the theodolite, and in a horizontal partial Vsectionthrough the micrometer device.

4 The centre .bearing b revolves in abush a of the base and is rigidly connected with a support c for the telescope'as well as with the casing c1 (the alidade c, c1) of the horizontal circle d. The horizontal circle (l, is

a part of the bush d1 which frictionally rests on the bush a of the base. On the said bush a a. ring e is rotatably provided. In order to be in a position, on one hand, to couple the alidade c, c1 with the said ring e for common rotation and, on the other hand, to

allow line adjustments 'of the alidade c, c1 relatlvely to the said ringe, the following arrangement is made. The ring eis provided wlth a branch e1. Against a shoulder e2 o this branch there acts from one side the point f of a screw f2 provided with amilled .head f1 and, from the other side, the point g of a hollow pin g?. The thread of the screw f2 engages in a female fitting h which in its vturn is screwed in 'a shoulder c2 of the round caslng e1. The hollow pin g1 slides in a fitted block z' which is screwed. in a second shoulder c* of the round casing c1.,V In the hollow pin g 1 there is provided a spring c'which contmuously presses the point g of the hollow pin g1 against the shoulder e2 of the branch e1 and, consequently, the shoulder c2 'against the point f of the screw f. In order to be in a positlon to adjustthe ring e and, consequently, also the alidade c, c1 relatively to the bush a of the base, the branch e1 is provided inside with a pressure bolt l which can be .pressed on the said bush a by. means of a screwm1 having a milled hea m. The

Ysleeve d1 has an easily iexible disc a screwed on. In order to have the horizontal circle i d clamped to the round casing c1, the said disc 'n can be pressed against a shoulder c'4 of the round cover c1 by means of a .bolt o and a lever p attached excentrically on the round casing o1.' For the reading of the horizontal angles, the round casing is provided with a vernierl cco-acting with the horizontalcircle d. i

The procedure* ofthe repetition, which, as is well known, 'serves for {repeating several times the measuring of-the azimuthal angle4 so as to attainpincreased exaetness, isasfol-v lows. The clamps m and Yp having beenv loosened, the alidade c, `c1 is turned relatively to the base a in such a way that the vtelesco e (not shown in the drawing) of the theodohte is in rough alignmentpwith the first aim.

Then, by 'turning the'milled head m, the

clamping screw m1 is tightened and, by turning the milled head f1 of themicrometer screw f2, the telescope is brought into exact alignment with the said aim. Now, the first reading must 4be taken onjthe horizontal circle I After having loosened'the clamping screw the telescope support and adapted to press the said disc against the telescope support, and an adjusting device provided on the telescope support and adapted to adjust the telescope support relatively to the base.

' JOSEPH MAHLER.

is loosened again and the telescope turned back into rough alignment with the first aim, whereby also the circle is taken along. m1 having been tightened, the telescope is brought into exact alignment with the first i aim by turning the micrometer screw f2. Hereupon, by turning the lever p, the clamping of the circle d with the alidade c, c1 is to be loosened again. The above proceeding can be repeated now as many times as may be required. A iinal reading has to be taken and the angle between the two aims, with its vertex on the site of the instrument, calculated as a mean value by means ofthe quotient of the difference between the final and the first reading and of the number of repetitions.

I claim 1. A stand for a repeating theodolite, comprising a base. a telescope support and a horizontal circle, both rotatably disposed on the base, there being a pointer fixed on the telescope support and qoacting with the horizontal circle, two clamping devices attached to the telescope support, these two devices being adapted to clamp the telescope support with the base and the horizontal circle respectively, and an adjusting device provided on the telescope support and adapted to adjjust the telescope support relatively to the ase.

2. A standfor a repeating theodolite, comprising a base` a telescope support and a horizontal circle, both rotatably disposed on the base, there being a pointer fixed on the telescope support and coacting with the horizontal circle, a clamping device attached to the telescope support and adapted to clamp the telescope support to the base, a flexible disc fixed to the horizontal circle, means provided on the telescope support and adapted to press the said disc against the telescope support, and an adjusting device provided on the telescope support, and adapted to adjust the telescope support relatively to the base.

3. A stand for a repeating theodolite, comprising a base, a telescope support and a horizontal circle, both rotatably disposed on the base, a casing provided on the telescope support and covering the horizontal circle, there being a pointer fixed on the casing and coacting with the horizontal circle, a clamping device attached to the telescope support and adapted to clamp the telescope support to the base, a fiexible disc fixed to the lower side of the horizontal circle, means provided on 

